In order to increase an effect of cancer treatment without damage of normal tissue by irradiating cancer tissue with an optimal radiation dose for cancer tissue and irradiating normal tissue around the cancer tissue with a minimum radiation dose at the same time during radiation treatment for cancer, research on radiation treatment planning (RTP) to make a plan for a radiation dose according to a state of cancer in a patient has been performed.
The RTP, which is related to calculation and verification of a radiation dose and generation of radiation treatment information, is made through a computer simulation using diagnostic images of a patient, for example, 3D computed tomography (CT) images or average intensity projection (AVE-IP) of 4D CT images.
The diagnostic images of the patient cannot reflect movement of internal organs according to breathing, and thus, may cause a difference between a dose of RTP and a dose of actual radiation treatment. A greater dose difference may occur especially when RTP about a tumor generated in an organ with a large movement, for example, a lung, a liver, or a pancreas. Furthermore, a much greater dose difference may occur when radiation treatment using charged particles irradiating a local area with many doses or spot-scanning radiation treatment irradiating a tumor of a patient with radiation by moving a beam along a shape of the tumor is performed. However, if a breathing period of a patient is further subdivided to reflect movement of the internal organ to prevent the dose difference, and thus, more diagnostic images are acquired and an exposure dose of the patient may increase.
In general, a calculation of a dose when making RTP includes a separate process of calculating a dose of each of diagnostic images of a patient by performing a computer simulation and matching each of the dose calculation results with a specific reference image. As a result, a time for RTP is longer and it is difficult to simplify and automate a dose calculation process.